DS11 did/does the same thing. The noises and arm movements were really noticeable when he was younger but they’ve mostly stopped and now he just paces when he does it which is way less than he used to.
At recess now he plays role playing games with other kids based on books like Harry Potter and Warriors (fifth graders hissing at each other must be hilarious to see).
Basically he’s outgrowing the quirky part but movement is the way he thinks through stuff and accesses his imagination. Given that a lot of adults go for a walk or run or ride when they have a lot on their mind, I suspect he will be one of those.
